Crystal structure, Hirshfeld surface analysis, inter-action energy and energy framework calculations, as well as density functional theory (DFT) com-putation, of methyl 2-oxo-1-(prop-2-yn-yl)-1,2-di-hydro-quinoline-4-carboxyl-ate

Abstract

In the title mol-ecule, C₁₄H₁₁NO₃, the di-hydro-quinoline core deviates slightly from planarity, indicated by the dihedral angle of 1.07 (3)° between the two six-membered rings. In the crystal, layers of mol-ecules almost parallel to the bc plane are formed by C-H⋯O hydro-gen bonds. These are joined by π-π stacking inter-actions. A Hirshfeld surface analysis revealed that the most important contributions to the crystal packing are from H⋯H (36.0%), H⋯C/C⋯H (28.9%) and H⋯O/O⋯H (23.5%) inter-actions. The evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the dispersion energy contribution. Moreover, the mol-ecular structure optimized by density functional theory (DFT) at the B3LYP/6-311G(d,p) level is com-pared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Keywords: C—H⋯O hydro­gen bonds; crystal structure; di­hydro­quinoline; π-stacking.

Figure 1

The mol­ecular structure of the title com­pound with the atom-labeling scheme and displacement ellipsoids drawn at the 50% probability level.

Figure 2

A partial packing diagram, viewed down the a axis, with C—H⋯O hydro­gen bonds shown as dashed lines.

Figure 3

View of the three-dimensional Hirshfeld surface of the title com­pound, plotted over d _norm in the range from −0.1226 to 1.1991 a.u.

Figure 4

View of the three-dimensional Hirshfeld surface of the title com­pound plotted over electrostatic potential energy in the range from −0.0500 to 0.0500 a.u., using the STO-3G basis set at the Hartree–Fock level of theory.

Figure 5

The Hirshfeld surface of the title com­pound plotted over shape-index.

Figure 6

The full two-dimensional fingerprint plots for the title com­pound, showing (a) all inter­actions, (b) H⋯H, (c) H⋯C/C⋯H, (d) H⋯O/O⋯H, (e) C⋯C, (f) C⋯O/O⋯C, (g) H⋯N/N⋯H, (h) C⋯N/N⋯C and (i) N⋯O/O⋯N inter­actions. The d _i and d _e values are the closest inter­nal and external distances (in Å) from given points on the Hirshfeld surface contacts.

Figure 7

The Hirshfeld surface representations with the function d _norm plotted onto the surface for (a) H⋯H, (b) H⋯C/C⋯H and (c) H⋯O/O⋯H inter­actions.

Figure 8

The energy frameworks, viewed down the c axis, for a cluster of mol­ecules of the title com­pound, showing the (a) electrostatic energy, (b) dispersion energy and (c) total energy diagrams, where the b axis is vertical and the c axis is horizontal. The cylindrical radius is proportional to the relative strength of the corresponding energies and was adjusted to the same scale factor of 80 with a cut-off value of 5 kJ mol⁻¹ within 2 × 2 × 2 unit cells.

Figure 9

The energy band gap of the title com­pound.

Figure 10

The mol­ecular moiety used for the database search.